JP7008190B2 - Adhesive or adhesive sheets and laminates - Google Patents

Description

The present disclosure relates to adhesive or adhesive sheets, laminates, and methods of using adhesive or adhesive sheets.

Conventionally, adhesive or adhesive films or tapes for fixing parts in products such as semiconductor devices, electronic devices, and electric appliances are known.

For example, Patent Document 1 describes an adhesive film material for insulatingly adhering a wiring tape and a semiconductor element in a semiconductor device. The elastic modulus of the adhesive film material in the temperature range (200 to 250 ° C.) under the mounting reflow conditions is 1 MPa or more. This adhesive film material can function as a stress buffering layer. According to this adhesive film material, it is suggested that the height difference can be adjusted within 5 μm for a thickness of about 150 μm.

Patent Document 2 describes a thin double-sided adhesive tape used for a housing of a portable electronic device and a joint portion of parts. This double-sided adhesive tape has an adhesive layer on both sides of a support made of a resin film. The total thickness of the double-sided adhesive tape is 2 to 10 μm. The support is, for example, a polyethylene terephthalate (PET) film.

Japanese Unexamined Patent Publication No. 9-321084 Japanese Unexamined Patent Publication No. 2013-14723

According to the techniques described in Patent Documents 1 and 2, there is room for reducing the thickness of the adhesive or adhesive film or tape. Therefore, the present disclosure provides a thinner adhesive or adhesive sheet.

This disclosure is
It has a cellulose-containing structure capable of retaining adhesive or adhesive components, and has a thickness of 100 nm to 2 μm.
An adhesive or adhesive sheet is provided.

Additional effects and advantages of the disclosed embodiments will be apparent from the specification and drawings. The effects and / or advantages are provided individually by the various embodiments or features disclosed in the specification and drawings, and not all are required to obtain one or more of these.

The adhesive or adhesive sheet described above is thinner.

FIG. 1 is a cross-sectional view schematically showing an example of the adhesive or adhesive sheet of the present disclosure. FIG. 2 is a cross-sectional view schematically showing an example of the laminated body of the present disclosure. FIG. 3 is a diagram showing an example of how to use the adhesive or adhesive sheet of the present disclosure. FIG. 4 is a diagram showing another example of how to use the adhesive or adhesive sheet of the present disclosure. FIG. 5 is a graph showing the thickness of the laminated body in the sample according to the example and the sample according to the comparative example.

(Findings underlying this disclosure)
Reducing the thickness of the adhesive or adhesive sheet is advantageous in reducing the height of the parts or products obtained by using the adhesive or adhesive sheet. According to the technique described in Patent Document 1, since the thickness of the adhesive film material is 50 to 200 μm, it is difficult to reduce the gap between articles to 50 μm or less, which is advantageous from the viewpoint of reducing the height of parts or products. It's hard to say. In addition, depending on the adhesive film material, there is a possibility that a height difference of about 5 μm may occur, and the technique described in Patent Document 1 has room for improvement from the viewpoint of suppressing the inclination between articles.

The double-sided adhesive tape described in Patent Document 2 has a total thickness of 2 to 10 μm, and according to the technique described in Patent Document 2, it is difficult to make the total thickness of the double-sided adhesive tape thinner than 2 μm. In the examples of Patent Document 2, the minimum value of the total thickness of the double-sided adhesive tape is 3 μm. In the double-sided adhesive tape described in Patent Document 2, the support is, for example, a PET film. It is considered that the pressure-sensitive adhesive layer exists on the surface of the support without entering the support in the thickness direction of the double-sided adhesive tape. Therefore, according to the double-sided adhesive tape described in Patent Document 2, peeling may occur at the interface between the support and the adhesive layer, and it is considered that the adhesiveness of the double-sided adhesive tape is difficult to be maintained for a long period of time. ..

In order to reduce the gap between the articles, it is conceivable to apply a liquid pressure-sensitive adhesive or an adhesive to the adherend. However, it is difficult to apply a liquid adhesive or an adhesive uniformly and thinly to the adherend. For this reason, spatial variation of the pressure-sensitive adhesive layer or the adhesive layer formed by the liquid pressure-sensitive adhesive or the adhesive may occur, which may lead to tilting between articles. In addition, it is possible that the liquid pressure-sensitive adhesive or adhesive easily squeezes out from the adherend, and the squeeze-out of the pressure-sensitive adhesive or adhesive may cause problems such as poor insulation.

Therefore, the present inventors have repeatedly studied day and night on an adhesive or adhesive sheet having a thickness of 2 μm or less and capable of appropriately holding an adhesive or an adhesive. As a result, it has been newly found that a predetermined structure containing cellulose is advantageous from the viewpoint of reducing the thickness of the adhesive or adhesive sheet and appropriately retaining the adhesive or adhesive. Based on this new finding, the present inventors have devised the adhesive or adhesive sheet of the present disclosure.

The outline of the aspects according to the present disclosure is as follows.

(Item 1)
An adhesive or adhesive sheet having a cellulose-containing structure capable of retaining an adhesive or adhesive component and having a thickness of 100 nm to 2 μm.

(Item 2)
The adhesive or adhesive sheet according to item 1, wherein the cellulose is a regenerated cellulose having a weight average molecular weight of 100,000 or more.

(Item 3)
Item 2. The adhesive or adhesive sheet according to Item 1 or 2, wherein the component is continuously present between the surface of the adhesive or adhesive sheet and the cellulose in the thickness direction of the adhesive or adhesive sheet.

(Item 4)
The adhesive or adhesive sheet according to item 3, wherein the content of the component in the adhesive or adhesive sheet is 2% by weight or more.

(Item 5)
The adhesive or adhesive sheet according to any one of items 1 to 4, wherein the structure is a porous structure.

(Item 6)
The adhesive or adhesive sheet according to any one of items 1 to 5, which has an adhesive strength of 0.1 N / cm or more.

(Item 7)
The adhesive or adhesive sheet according to any one of items 1 to 6, which holds a thermoplastic adhesive or a thermosetting adhesive as the component.

(Item 8)
The adhesive or adhesive sheet according to any one of items 1 to 5, which holds an adhesive main agent or a curing agent that cures the adhesive main agent as the component.

(Item 9)
The adhesive or adhesive sheet according to any one of items 1 to 8 and the adhesive sheet.
A protective layer that is placed on the first main surface of the adhesive or adhesive sheet, is removable from the first main surface, and is permeable to a liquid that dissolves or swells the component.
Laminated body.

(Item 10)
The second main surface of the adhesive or adhesive sheet located on the opposite side of the first main surface is brought into contact with the adherend, and the laminate according to item 9 is attached to the adherend.
A liquid that dissolves or swells the component is supplied to the protective layer to exfoliate the protective layer from the first main surface.
How to use an adhesive or adhesive sheet.

(Item 11)
The adhesive or adhesive sheet according to item 8 holding the adhesive main agent and the adhesive or adhesive sheet according to item 8 holding the curing agent. how to use.

(Item 12)
A method for using an adhesive or adhesive sheet, wherein the adhesive or adhesive sheet according to any one of items 1 to 8 is brought into contact with an adherend to heat the adhesive or adhesive sheet.

(Embodiment)
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following embodiments are merely examples, and the method of using the adhesive or adhesive sheet, the laminate, and the adhesive or adhesive sheet of the present disclosure is not limited to the following embodiments. Matters such as numerical values, shapes, materials, components, arrangement of components, connection modes, and steps and order of steps shown in the following embodiments are examples and are described for the purpose of limiting the present disclosure. It's not a thing. The following various embodiments can be combined with each other as long as there is no conflict. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept should not be understood as essential components. In the following description, components having substantially the same function are indicated by common reference numerals, and the description may be omitted. In addition, some elements may be omitted in order to prevent the drawings from becoming excessively complicated.

The adhesive or adhesive sheet 10a shown in FIG. 1 has a structure containing cellulose. The structure preferably contains cellulose as the main component. As used herein, the term "main component" means the component most abundantly contained on a mass basis. This structure is capable of retaining adhesive or adhesive components. In the present specification, "adhesive" means that the sheet 10a is attached to an object so that the sheet 10a can be peeled off without breaking or deforming, and "adhesive" means a state other than "adhesive". Means that the sheet 10a is attached to the object. The sheet 10a has a thickness of 100 nm to 2 μm. The thickness of the sheet 10a is determined, for example, by measuring the thicknesses of the sheets 10a at a plurality of locations and averaging them. The thickness at each location can be measured using, for example, a stylus profiling system (manufactured by Bruker Nano Incorporated, product name: DEKTAK®).

Since the sheet 10a has a thickness of 100 nm to 2 μm, when two articles are joined using the sheet 10a, the gap between the articles can be reduced and the inclination between the articles can be suppressed. Further, in the sheet 10a, since the adhesive or adhesive component can be retained in the structure containing cellulose, the adhesive or adhesive component is appropriately retained in this structure, and there is little spatial variation in the thickness of the sheet 10a. .. In addition, the adhesive or adhesive component does not easily squeeze out from the edge of the sheet 10a.

Cellulose is, for example, cellulose substantially represented by the following formula (I). Here, "substantially the cellulose represented by the formula (I)" means the cellulose in which the hydroxyl group of the glucose residue in the cellulose represented by the formula (I) remains at 90% or more. The ratio of the number of hydroxyl groups of the glucose residue in the cellulose contained in the sheet 10a to the number of the hydroxyl groups of the glucose residue in the cellulose represented by the formula (I) is determined by, for example, X-ray photoelectron spectroscopy (XPS) or the like. It can be quantified by a known method. In some cases, the cellulose contained in the sheet 10a may contain a branched structure. Artificially derivatized cellulose typically does not fall under "substantially the cellulose represented by formula (I)". On the other hand, cellulose regenerated through derivatization is not excluded from "cellulose represented by the formula (I) substantially". Even cellulose that has been regenerated through derivatization may fall under "cellulose represented by the formula (I) substantially".

Cellulose is, for example, regenerated cellulose having a weight average molecular weight of 100,000 or more. Cellulose has a molecular structure containing many hydroxyl groups. In a sheet composed of cellulose, many hydrogen bonds are likely to occur inside or between molecules. Therefore, the sheet made of cellulose tends to have higher strength than the sheet made of other organic polymers. However, the strength of the sheet formed from a suspension in which natural cellulose fibers are dispersed in a dispersion medium such as water is borne by hydrogen bonds between the nanofibers constituting the cellulose fibers. Therefore, such a sheet has room for higher strength. On the other hand, in the sheet made of regenerated cellulose, the nanofibers are in a state of being loosened to the unit of the molecular chain, so that the strength of the sheet made of regenerated cellulose is borne by the hydrogen bond between the cellulose molecular chains. In a sheet made of regenerated cellulose, hydrogen bonds between units smaller than those of nanofibers are likely to be formed. Therefore, the sheet made of regenerated cellulose has higher strength and moderate flexibility than the sheet formed from a suspension in which fibers of natural cellulose are dispersed in a dispersion medium such as water. Has. Therefore, when the sheet 10a has a structure containing regenerated cellulose, the sheet 10a is hard to tear and easy to handle despite the thickness of 100 nm to 2 μm. The "nanofiber" is also called "nanofibril or microfibril" and is the most basic unit in which cellulose molecules are aggregated, and has a wire diameter of about 4 nm to about 100 nm and a length of about 1 μm or more.

In the sheet 10a, it is advantageous that the regenerated cellulose has a weight average molecular weight of 100,000 or more from the viewpoint of increasing the strength of the sheet 10a. This is because, in addition to increasing the strength along the extending direction of the molecular chain, more hydroxyl groups are contained in each molecular chain, so that more hydrogen bonds are formed between the molecules to increase the strength of the membrane. Because it can be considered. The weight average molecular weight of regenerated cellulose can be determined by gel permeation chromatography (GPC). A sample for GPC measurement can be prepared by extracting an adhesive or adhesive component from the sheet 10a.

As used herein, "regenerated cellulose" means cellulose that does not have the crystal structure I peculiar to natural cellulose. The crystal structure of cellulose can be confirmed by the XRD pattern. Natural cellulose has peaks near 14-17 ° and 23 °, which are peculiar to crystal structure I, in the XRD pattern using CuKα rays, but regenerated cellulose often has crystal structure II, 12 ° and 20 °. It has peaks near ° and 22 ° and no peaks near 14-17 ° and 23 °.

For example, 90% or more of the regenerated cellulose contained in the sheet 10a is regenerated cellulose that has not been chemically modified or derivatized. 98% or more of the regenerated cellulose contained in the sheet 10a may be regenerated cellulose which has not been chemically modified or derivatized. In this case, it is considered that the sheet 10a contains a large amount of regenerated cellulose that has not been chemically modified and derivatized, and contains a larger amount of hydroxyl groups per molecular chain of cellulose. Therefore, it is considered that more hydrogen bonds are formed between the molecules of cellulose, and the sheet 10a tends to have high strength. The regenerated cellulose contained in the sheet 10a may be uncrosslinked.

The heat resistant temperature of the regenerated cellulose can be, for example, 250 ° C. or higher. Also, regenerated cellulose does not have a glass transition point, for example, in the temperature range of −120 ° C. to 250 ° C. Further, for example, the coefficient of thermal expansion of regenerated cellulose is 1 ppm / K or less. This is advantageous for the sheet 10a to maintain high adhesive stability at high temperatures.

For example, the adhesive or adhesive component is continuously present between the surface of the sheet 10a and the cellulose in the thickness direction of the sheet 10a. As a result, when the sheet 10a is attached to the adherend, the layer formed by the adhesive or adhesive component is difficult to peel off from the sheet 10a. Therefore, the sheet 10a can be attached to the adherend for a long period of time. In addition, the adhesive or adhesive component is less likely to squeeze out from the edge of the sheet 10a more reliably.

As shown in FIG. 1, the sheet 10a has a first main surface 11 and a second main surface 12. The second main surface 12 is located on the opposite side of the first main surface 11. The adhesive or adhesive component forms, for example, the first main surface 11 and the second main surface 12 of the sheet 10a. In this case, the adhesive or adhesive component may be continuously present from the first main surface 11 to the second main surface 12 of the sheet 10a across the structure containing cellulose in the thickness direction of the sheet 10a. .. In this case, the adherend can be attached to both main surfaces of the sheet 10a, and the sheet 10a tends to exhibit high adhesive strength or adhesive strength. The sheet 10a has a first layer of an adhesive or adhesive component forming the first main surface 11 and a second layer of the adhesive or adhesive component forming the second main surface 12, the first layer and the first layer. The two layers may be separated from each other in the thickness direction of the sheet 10a.

The content of the adhesive or adhesive component in the sheet 10a is, for example, 2% by weight or more. In this case, the sheet 10a tends to exhibit high adhesive strength or adhesive strength. The content of the adhesive or adhesive component in the sheet 10a is preferably 5% by weight or more. As a result, higher adhesive strength can be obtained.

The content of the adhesive or adhesive component in the sheet 10a is, for example, 90% by weight or less, preferably 50% by weight or less. As a result, the adhesive or adhesive component is less likely to squeeze out from the edge of the sheet 10a more reliably.

In the sheet 10a, the structure containing cellulose is preferably a porous structure. In this case, the adhesive or adhesive component easily enters the inside of the porous structure, and when the two articles are joined using the sheet 10a, the adhesive or adhesive component does not easily squeeze out from the edge of the sheet 10a. It is desirable that the porous structure has, for example, a through hole penetrating the porous structure in the thickness direction of the sheet 10a. As a result, the pressure-sensitive adhesive or the adhesive tends to be continuously present in the thickness direction of the sheet 10a, and the adhesion or the adhesive strength can be further increased.

The sheet 10a has, for example, an adhesive force of 0.1 N / cm or more. Thereby, an article such as a device or a film can be stably fixed by using the sheet 10a. The sheet 10a preferably has an adhesive force of 0.5 N / cm or more, and more preferably has an adhesive force of 1 N / cm or more. When the sheet 10a has an adhesive force of 1 N / cm or more, the article can be stably fixed even if the article to which the sheet 10a is attached vibrates. The adhesive strength of the sheet 10a can be measured according to the test method (method 1) specified in Japanese Industrial Standards (JIS) Z 0237: 2009.

The adhesive or adhesive component is, for example, an adhesive, an adhesive, an adhesive main agent, or an adhesive hardener. The pressure-sensitive adhesive may be a rubber-based pressure-sensitive adhesive, an acrylic-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, or a urethane-based pressure-sensitive adhesive.

The sheet 10a holds, for example, a thermoplastic adhesive, a thermosetting adhesive, or a synthetic rubber-based adhesive as an adhesive or adhesive component. The thermoplastic adhesive is, for example, an adhesive containing polyvinyl alcohol, acrylic resin, polyvinyl acetate, polyethylene, polyolefin, polyamide, polyester, or polyurethane as a main component. The thermosetting adhesive is, for example, an epoxy resin-based adhesive or a phenol resin-based adhesive.

The sheet 10a may hold, for example, an adhesive main agent or a curing agent that cures the adhesive main agent as an adhesive or adhesive component. In this case, the adhesive main agent is cured by the reaction between the adhesive main agent and the curing agent. In other words, the adhesive base and the curing agent provide a reactive adhesive. The reactive adhesive may be, for example, an epoxy resin-based adhesive or a silicone resin-based adhesive.

When the sheet 10a holds the adhesive, the sheet 10a may exert an adhesive force by volatilizing the solvent contained in the adhesive, or may exert an adhesive force by hot melting or thermosetting. good. Therefore, in an example of how to use the sheet 10a, the sheet 10a is brought into contact with the adherend to heat the sheet 10a.

For example, the sheet 10a may be provided as the laminated body 50a shown in FIG. The laminated body 50a includes a sheet 10a and a protective layer 20. The protective layer 20 is arranged on the first main surface 11 of the sheet 10a. The protective layer 20 is removable from the first main surface 11 and can allow a liquid that dissolves or swells the adhesive or adhesive component to permeate. The protective layer 20 can protect the first main surface 11 of the sheet 10a.

The laminated body 50a is used, for example, as follows. As shown in FIG. 3, the second main surface 12 of the sheet 10a is brought into contact with the adherend 60, and the laminated body 50a is attached to the adherend 60. The protective layer 20 is supplied with a liquid L that dissolves or swells an adhesive or adhesive component. For example, the liquid L is dropped from above the protective layer 20. The liquid L permeates the protective layer 20 and reaches the second main surface 12 of the sheet 10a, and dissolves or swells the adhesive or adhesive component in the vicinity of the second main surface 12. Thereby, the protective layer 20 can be easily peeled off from the first main surface 11 after that.

When the sheet 10a holds the adhesive base material, the sheet 10a is used, for example, together with the sheet 10b. The sheet 10b is configured in the same manner as the sheet 10a except that it holds a curing agent instead of the adhesive main agent. By laminating the sheet 10a and the sheet 10b, the sheet 10a and the sheet 10b can be used.

For example, as shown in FIG. 4, in a state where the sheet 10a and the sheet 10b are bonded between the first adherend 60a and the second adherend 60b, the sheet 10a and the sheet 10b are the second adherend 60b. It is pressed against the first adherend 60a by its own weight or an external force. As a result, the adhesive main agent and the curing agent are mixed, and the adhesive main agent is cured. As a result, the first adherend 60a and the second adherend 60b can be joined. The sheets 10a and 10b may be heated to accelerate the curing of the adhesive base. As a result, the curing time of the adhesive main agent can be significantly shortened. The first adherend 60a is, for example, a substrate, and the second adherend 60b is, for example, a component such as a device and a film.

When the adhesive main agent and the curing agent are held on the sheets 10a and the sheet 10b, respectively, the adhesive main agent and the curing agent can be stably stored for a long period of time, and these can be easily used. Moreover, since each of the sheet 10a and the sheet 10b is a thin sheet having a thickness of 100 nm to 2 μm, the adhesive main agent and the curing agent are easily mixed, and the cured state of the adhesive main agent is less likely to vary spatially.

An example of a method for manufacturing the adhesive or adhesive sheet 10a will be described. First, a cellulose solution is prepared by dissolving cellulose in a solvent. In order to obtain a regenerated cellulose membrane having a weight average molecular weight of 100,000 or more, cellulose having a weight average molecular weight of at least 100,000 or more is used. As a result, the sheet 10a having a thickness of 100 nm to 2000 nm or less can be produced. As described above, by increasing the weight average molecular weight of the cellulose used in the preparation of the cellulose solution, more hydroxyl groups are contained in the single molecular chain. This makes it possible to form many intermolecular hydrogen bonds, and a thinner adhesive or adhesive sheet can be stably produced. The cellulose used for preparing the cellulose solution is not particularly limited as long as it has a desired weight average molecular weight.

As the cellulose used for preparing the solution, either natural cellulose or regenerated cellulose can be used. The cellulose used to prepare the cellulose solution can be, for example, plant-derived cellulose such as pulp and cotton, or cellulose produced by an organism such as bacteria. The impurity concentration in the raw material of cellulose is, for example, 10% by weight or less. When the weight average molecular weight of the regenerated cellulose is 2,000,000 or less, it is useful because it is easy to handle. More preferably, the weight average molecular weight of the regenerated cellulose is 1,000,000 or less.

The solvent is, for example, a solvent containing at least an ionic liquid (first solvent). By using the first solvent, cellulose can be dissolved in a relatively short time. An ionic liquid is a salt composed of anions and cations and can exhibit a liquid state at a temperature of 150 ° C. or lower. The ionic liquid contained in the first solvent is, for example, an ionic liquid containing an amino acid or an alkyl phosphate ester. Since the first solvent contains such an ionic liquid, it is possible to dissolve cellulose while suppressing a decrease in the molecular weight of cellulose.

Cellulose may be dissolved using an ionic liquid pre-diluted with a solvent that does not precipitate cellulose. For example, a mixture of an aprotic polar solvent and an ionic liquid may be used as the first solvent. The aprotic polar solvent is difficult to form hydrogen bonds and difficult to precipitate cellulose.

The ionic liquid contained in the first solvent is, for example, an ionic liquid represented by the following formula (II). In the ionic liquid represented by the formula (II), the anion is an amino acid. As described in formula (II), in this ionic liquid, the anion contains a terminal carboxyl group and a terminal amino group. The cation of the ionic liquid represented by the formula (II) may be a quaternary ammonium cation.

In formula (II), R ₁ to R ₆ independently represent a hydrogen atom or a substituent. The substituent can be an alkyl group, a hydroxyalkyl group, or a phenyl group. The substituent may contain a branch in the carbon chain. The substituent may contain a functional group such as an amino group, a hydroxyl group, or a carboxyl group. n is, for example, 4 or 5.

The ionic liquid contained in the first solvent may be an ionic liquid represented by the following formula (III). In formula (III), R ₁ , R ₂ , R ₃ , and R ₄ independently represent an alkyl group having a hydrogen atom or 1 to 4 carbon atoms.

A second solvent may be further added in the step of preparing the cellulose solution. For example, the second solvent may be further added to the mixture of cellulose having a predetermined weight average molecular weight and the first solvent. The second solvent is, for example, a solvent that does not precipitate cellulose. The second solvent can be an aprotic polar solvent.

The concentration of cellulose in the cellulose solution is typically 0.2-15% by weight. When the concentration of cellulose in the cellulose solution is 0.2% by weight or more, the adhesive or adhesive sheet 10a having the strength necessary to maintain its shape while reducing the thickness of the adhesive or adhesive sheet 10a can be obtained. .. Further, when the concentration of cellulose in the cellulose solution is 15% by weight or less, the precipitation of cellulose in the cellulose solution can be suppressed. The concentration of cellulose in the cellulose solution may be 1 to 10% by weight. When the concentration of cellulose in the cellulose solution is 1% by weight or more, an adhesive or adhesive sheet 10a having higher strength can be obtained. When the concentration of cellulose in the cellulose solution is 10% by weight or less, a stable cellulose solution in which precipitation of cellulose is further reduced can be prepared.

Next, a cellulose solution is applied to the surface of the substrate to form a liquid film on the surface of the substrate. The contact angle of the surface of the substrate with water is, for example, 90 ° or less. In this case, the wettability of the cellulose solution to the substrate is appropriate, and a liquid film spreading along the surface of the substrate can be stably formed. The material of the substrate is not particularly limited. The substrate typically has a non-porous structure with a smooth surface. In this case, it is possible to prevent the cellulose solution from entering the inside of the substrate, and it is easy to separate the adhesive or adhesive sheet 10a from the substrate in a subsequent step.

The substrate may be chemically or physically surface modified. As the substrate, for example, a substrate made of a polymer material that has undergone surface modification treatment such as ultraviolet (UV) irradiation or corona treatment may be used. The method of surface modification is not particularly limited. For example, application of a surface modifier, surface modification, plasma treatment, sputtering, etching, or blasting may be applied.

The method of forming a liquid film of a cellulose solution on a substrate is, for example, a gap coating, a slot die coating, a spin coating, or a coating using a bar coater (Metering) that forms a predetermined gap between the substrate and the surface of the substrate by an applicator or the like. Rod coating), and methods such as gravure coating. The thickness of the liquid film adjusted by the thickness of the gap or the size of the opening of the slot die and the coating speed, the rotation speed of the spin coat, the depth of the groove of the bar coater or the gravure coat, the coating speed, etc., and the concentration of the cellulose solution. By adjusting, the thickness of the adhesive or adhesive sheet can be adjusted. The method of forming a liquid film of the cellulose solution on the substrate may be a casting method, screen printing using a squeegee, spray coating, or electrostatic spraying.

When forming a liquid film of the cellulose solution on the substrate, at least one of the cellulose solution and the substrate may be heated. This heating may be carried out, for example, in a temperature range (for example, 40 to 100 ° C.) at which the cellulose solution can be kept stable. The liquid film of the cellulose solution formed on the substrate may be heated. The heating of the liquid film may be performed, for example, at a temperature lower than the decomposition temperature of the ionic liquid contained in the first solvent (for example, 50 to 200 ° C.). By heating the liquid film at such a temperature, a solvent other than the ionic liquid (for example, a second solvent) can be appropriately removed, and the strength of the adhesive or adhesive sheet 10a tends to increase. The heating of the liquid film may be carried out in a reduced pressure environment. In this case, the solvent other than the ionic liquid can be appropriately removed in a shorter time at a temperature lower than the boiling point of the solvent.

After forming a liquid film of the cellulose solution on the substrate, the liquid film may be gelled. For example, by exposing the liquid film to the vapor of a liquid that can be dissolved in an ionic liquid and does not dissolve cellulose, the liquid film can be gelled to obtain a polymer gel sheet. For example, if the liquid film is left in an environment with a relative humidity of 30 to 100% RH, the ionic liquid in the liquid film comes into contact with water, and the solubility of cellulose in the liquid film decreases. As a result, a part of the cellulose molecule is precipitated and a three-dimensional structure is formed. As a result, the liquid film gels. The presence or absence of a gelation point can be determined by whether or not it is possible to lift the gelled membrane.

The heating of the liquid film may be performed before the gelation of the liquid film, after the gelation of the liquid film, or before and after the gelation of the liquid film. ..

Next, the substrate and the polymer gel sheet are immersed in a rinse liquid which is a liquid that does not dissolve cellulose. In this step, the ionic liquid is removed from the polymer gel sheet. This step can be understood as the step of cleaning the polymer gel sheet. In this step, in addition to the ionic liquid, a part of the components other than the cellulose and the ionic liquid (for example, the second solvent) may be removed from the components contained in the cellulose solution. The rinse liquid is typically a liquid that is soluble in ionic liquids. Examples of such liquids are water, methanol, ethanol, propanol, butanol, octanol, toluene, xylene, acetone, acetonitrile, dimethylacetamide, dimethylformamide, and dimethyl sulfoxide.

Next, the polymer gel sheet is immersed in a solution of adhesive or adhesive components. Solvents in the solution of the adhesive or adhesive component are, for example, water, methanol, ethanol, propanol, butanol, acetone, glycerin, propanediol, 1,3-butanediol, 1,4-butanediol, diglycerin, polyethylene glycol, dimethicone. , Tetrahydrofuran (THF), toluene, methyl acetate, ethyl acetate, tetrachloroethylene, petroleum ether, acetonitrile, diethyl ether, methylene chloride, chloroform, NN-dimethylformamide, acetic acid, formic acid, hexane, and at least selected from the group consisting of decane. There is one. Instead of immersing the polymer gel sheet in a solution of the adhesive or adhesive component, the adhesive or adhesive component may be attached to the polymer gel sheet by spraying, vapor deposition, or coating. The polymer gel sheet may be immersed in a solution, a dispersion, or an emulsion containing the above-mentioned active ingredient, separately from the immersion of the adhesive or adhesive component in the solution.

Next, unnecessary components such as a solvent are removed from the polymer gel sheet. In other words, the polymer gel sheet is dried. As a method for drying the polymer gel sheet, drying methods such as natural drying, vacuum drying, heat drying, freeze drying, and supercritical drying can be applied. The method for drying the polymer gel sheet may be vacuum heating. The conditions for drying the polymer gel sheet are not particularly limited. Sufficient time and temperature for removing the second solvent and the rinsing solution are selected as the conditions for drying the polymer gel sheet. By removing the solvent from the polymer gel sheet, an adhesive or adhesive sheet 10a is obtained.

When freeze-drying or supercritical drying is applied in the step of drying the polymer gel sheet, a porous structure adhesive or adhesive sheet having a lower bulk density is applied as compared with the case where natural drying, vacuum drying, or heat drying is applied. Is easy to obtain. By having a porous structure, many adhesives or adhesives can be retained. Further, when a solvent is used at the time of sticking, the solvent can be easily permeated into the adhesive or adhesive sheet, and the sticking can be easily performed. In the step of drying the polymer gel sheet, for example, when freeze-drying is applied, a solvent that can be frozen and has a boiling point of about 100 to 200 ° C. is used. For example, freeze-drying can be performed using a solvent such as water, tert-butyl alcohol, acetic acid, 1,1,2,2,3,3,4-heptafluorocyclopentane, or dimethyl sulfoxide.

In the above method, the polymer gel sheet is adhered or dipped in a solution of the adhesive component prior to the drying of the polymer gel sheet. However, after the polymer gel sheet is dried, the step of adhering the adhesive or the adhesive component is performed. It may be done. For example, the polymer sheet obtained by drying the polymer gel sheet may be immersed in a solution of an adhesive or adhesive component. Then, the polymer sheet after immersion is further dried. In this case as well, the adhesive or adhesive component may be attached to the polymer gel sheet by a spraying method, vapor deposition, or coating.

The adhesive or adhesive sheet of the present disclosure will be described in more detail by way of examples. The adhesive or adhesive sheet of the present disclosure is not limited to the following examples.

(Example 1)
A wood-based bleached pulp having a cellulose purity of 90% or more was prepared. The weight average molecular weight of cellulose contained in bleached pulp was measured by the Gel Permeation Chromatography (GPC) -Multi Angle Light Scattering (MALS) method and found to be about 230,000. For this measurement, a liquid feed unit LC-20AD manufactured by Shimadzu Corporation was used, and a differential refractometer Optilab rEX manufactured by Wyatt Technology Corporation and a multi-angle light scattering detector DAWN HELEOS were used as detectors. TSKgel α-M manufactured by Tosoh Corporation was used as the column, and a dimethylacetamide solution of lithium chloride (lithium chloride concentration: 0.1 M) was used as the solvent. The measurement was performed under the conditions of column temperature: 23 ° C. and flow rate: 0.8 mL / min.

The bleached pulp was dissolved in an ionic liquid to prepare a cellulose solution. Ethylmethylimidazolium diethyl phosphate was used as the ionic liquid. Next, a gap coating was applied to apply a cellulose solution to the surface of the glass substrate to form a coating film on the glass substrate. At this time, the size of the gap in the gap coating was adjusted with the aim of making the thickness of the adhesive sheet 1 μm. Then, the coating film was washed to remove the ionic liquid from the coating film to obtain a polymer gel sheet.

An adhesive containing a vinyl acetate resin as a main component was dissolved in pure water to prepare an aqueous solution of the adhesive (adhesive concentration: 10% by weight). The polymer gel sheet was immersed in the aqueous solution of the adhesive, and the aqueous solution of the adhesive was impregnated into the polymer gel sheet. Then, the polymer gel sheet was placed on a non-woven fabric permeable to a solvent and dried to obtain an adhesive sheet according to Example 1. The content of the adhesive in the adhesive sheet according to Example 1 was confirmed by a spectrophotometer UV-1600 (Shimadzu Corporation) using a solution obtained by extracting the adhesive from the adhesive sheet. The content of the adhesive in the adhesive sheet according to Example 1 was 9.2% by weight. The thickness of the adhesive sheet according to Example 1 was measured using a stylus-type profiling system (manufactured by Bruker Nano Incorporated, trade name: DEKTAK (registered trademark)). As a result, the thickness of the adhesive sheet according to Example 1 was about 950 nm. The thickness of the adhesive sheet according to Example 1 was determined by measuring the thickness of the adhesive sheet at a plurality of points and averaging them.

The adhesive sheet installed on the non-woven fabric according to Example 1 is attached so that the adhesive sheet surface is in contact with the slide glass, a small amount of water (about 10 μL) is dropped from the non-woven fabric, and the non-woven fabric is attached to the adhesive sheet after about 10 seconds. I peeled it off from. A commercially available PET film having a thickness of 100 μm is pressed against the adhesive sheet using a roller with a linear load of 1 kg / cm, and the roller is reciprocated 10 times to adhere the PET film to the slide glass, and the sample according to Example 1. Got The PET film had a square shape of 2 cm square. In the sample according to Example 1, the PET film was attached to the adhesive sheet without the adhesive squeezing out from the edge of the adhesive sheet, and the PET film could be stably adhered to the slide glass.

(Example 2)
In Example 2 in the same manner as in Example 1 except that the polymer gel sheet was impregnated with an acetone solution of a silyl urethane resin adhesive (adhesive concentration: 10% by weight) instead of the adhesive aqueous solution. The adhesive sheet was obtained. The content of the adhesive in the adhesive sheet according to Example 2 was 10.1% by weight. The thickness of the adhesive sheet according to Example 2 was about 1030 nm. The thickness of the adhesive sheet according to Example 2 was determined in the same manner as in Example 1.

A PET film was applied to the slide glass using the adhesive sheet according to Example 2 in the same manner as the adhesive sheet according to Example 1 except that a small amount of acetone (about 10 μL) was used instead of a small amount of water. It was adhered to obtain a sample according to Example 2. In the sample according to Example 2, the PET film was attached to the adhesive sheet without the adhesive squeezing out from the edge of the adhesive sheet, and the PET film could be stably adhered to the slide glass.

(Example 3)
An adhesive sheet according to Example 3 was obtained in the same manner as in Example 2 except that the concentration of the acetone solution of the silyl urethane resin adhesive was adjusted to 2.5% by weight. The content of the adhesive in the adhesive sheet according to Example 3 was 1.7% by weight. The thickness of the adhesive sheet according to Example 3 was about 970 nm. The thickness of the adhesive sheet according to Example 3 was determined in the same manner as in Example 1.

In the same manner as the adhesive sheet according to Example 2, the PET film was adhered to the slide glass using the adhesive sheet according to Example 3, and a sample according to Example 3 was obtained. In the sample according to Example 3, the PET film was attached to the adhesive sheet without the adhesive squeezing out from the edge of the adhesive sheet, and the PET film could be stably adhered to the slide glass.

(Example 4)
An adhesive sheet according to Example 4 was obtained in the same manner as in Example 2 except that the concentration of the acetone solution of the silyl urethane resin adhesive was adjusted to 5% by weight. The content of the adhesive in the adhesive sheet according to Example 4 was 4.2% by weight. The thickness of the adhesive sheet according to Example 4 was about 1000 nm. The thickness of the adhesive sheet according to Example 4 was determined in the same manner as in Example 1.

In the same manner as the adhesive sheet according to Example 2, the PET film was adhered to the slide glass using the adhesive sheet according to Example 4, and a sample according to Example 4 was obtained. In the sample according to Example 4, the PET film was attached to the adhesive sheet without the adhesive squeezing out from the edge of the adhesive sheet, and the PET film could be stably adhered to the slide glass.

(Example 5)
An adhesive sheet according to Example 5 was obtained in the same manner as in Example 4 except that the size of the gap in the gap coating was adjusted with the aim of achieving a thickness of the adhesive sheet of 2 μm. The content of the adhesive in the adhesive sheet according to Example 5 was 4.5% by weight. The thickness of the adhesive sheet according to Example 5 was about 1950 nm. The thickness of the adhesive sheet according to Example 5 was determined in the same manner as in Example 1.

In the same manner as the adhesive sheet according to Example 2, the PET film was adhered to the slide glass using the adhesive sheet according to Example 5, and a sample according to Example 5 was obtained. In the sample according to Example 5, the PET film was attached to the adhesive sheet without the adhesive squeezing out from the edge of the adhesive sheet, and the PET film could be stably adhered to the slide glass.

(Comparative Example 1)
An adhesive containing vinyl acetate resin as a main component was applied onto the slide glass in an amount of 0.0075 g / cm ² . Then, a commercially available PET film having a thickness of 100 μm is pressed against the slide glass with a linear load of 1 kg / cm by using a roller to reciprocate the roller 10 times, whereby the PET film is adhered to the slide glass, and the present invention relates to Comparative Example 1. A sample was obtained. The PET film had a square shape of 2 cm square. In the sample according to Comparative Example 1, it was confirmed that the adhesive squeezed out around the PET film adhered to the slide glass.

(Comparative Example 2)
A PET film was adhered to a slide glass in the same manner as in Comparative Example 1 except that a silyl urethane resin adhesive was used instead of the adhesive containing vinyl acetate resin as a main component, and a sample according to Comparative Example 2 was obtained. rice field. In the sample according to Comparative Example 2, it was confirmed that the adhesive squeezed out around the PET film adhered to the slide glass.

(Comparative Example 3)
Recycled paper double-sided tape (manufactured by Nichiban Co., Ltd., product name: Nystack (registered trademark)) holding an acrylic adhesive was attached to the slide glass, and the release liner was peeled off. Then, a commercially available PET film having a thickness of 100 μm is pressed against the slide glass with a linear load of 1 kg / cm by using a roller to reciprocate the roller 10 times, whereby the PET film is adhered to the slide glass, and the present invention relates to Comparative Example 3. A sample was obtained. The PET film had a square shape of 2 cm square. In the sample according to Comparative Example 3, no squeeze out of the adhesive was confirmed around the PET film adhered to the slide glass.

In the samples according to Examples 1 to 5 and the samples according to Comparative Examples 1 to 3, the thickness of the laminate of the adhesive sheet, the adhesive layer, or the double-sided tape and the PET film was measured. The thickness of the laminated body was measured 10 times in total, once at 10 points separated from each other by 1 mm or more. The thickness of the laminate corresponds to the height of the PET film from the adherend surface of the slide glass. The results are shown in FIG. As shown in FIG. 5, in the samples according to Examples 1 to 5, the difference obtained by subtracting the PET film thickness (100 μm) from the height of the PET film from the adherend surface of the slide glass was within 2 μm. In addition, the standard deviation of the difference was a very small value within 2 μm. On the other hand, in the samples according to Comparative Examples 1 to 3, the difference obtained by subtracting the PET film thickness (100 μm) from the height of the PET film from the adherend surface of the slide glass reached 30 μm or more. In addition, in the samples according to Comparative Examples 1 to 3, the standard deviation of the difference was a large value of 4 μm or more. The adhesive state of the PET film in the samples according to Examples 1 to 5 and the samples according to Comparative Examples 1 to 3 was evaluated according to the following criteria. The results are shown in Table 1.
<Average value of thickness>
A: The average value of the difference Δt obtained by subtracting the PET film thickness (100 μm) from the height of the PET film from the adherend surface of the slide glass is less than 2 μm.
B: The average value of the difference Δt is 2 μm or more and less than 4 μm.
C: The average value of the difference Δt is 4 μm or more.
<Variation in thickness>
A: The standard deviation of the difference Δt is less than 2 μm.
B: The standard deviation of the difference Δt is 2 μm or more and less than 4 μm.
C: The standard deviation of the difference Δt is 4 μm or more.

<Wearability>
In the samples according to Examples 1 to 5 and the samples according to Comparative Examples 1 to 3, an adhesive tape having an adhesive force of 0.1 N / cm, 1.1 N / cm, and 8 N / cm was applied with a linear load of 1 kg / cm. It was pasted on a PET film. This adhesive strength is determined according to the test method (method 1) specified in JIS Z 0237: 2009. It was confirmed whether or not the PET film was peeled off from the slide glass when the adhesive tape was peeled off. Except for the case where an adhesive tape having an adhesive force of 8 N / cm was used for the sample according to Example 3, in the samples according to Examples 1 to 5 and the samples according to Comparative Examples 1 to 3, from the slide glass of the PET film. No peeling was confirmed. The results are shown in the wearable column in Table 1. In this column, "OK" indicates that the peeling of the PET film from the slide glass was not confirmed, and "NG" indicates that the peeling of the PET film from the slide glass was confirmed.

<Adhesive squeeze out>
In the samples according to Examples and Comparative Examples, the case where the adhesive protrudes 1 mm or more from the edge of the PET film is evaluated as NG, and the case where the adhesive does not protrude 1 mm or more from the edge of the PET film is OK. I evaluated it. The results are shown in Table 1.

As shown in Table 1, in the samples according to Comparative Examples 1 and 2, the adhesive squeezed out, and in the samples according to Comparative Examples 1 to 3, the average value and standard deviation of the above difference Δt were large. On the other hand, in the samples according to Examples 1 to 5, no squeeze out of the adhesive was confirmed, and the average value and standard deviation of the difference Δt were small.

10a, 10b Adhesive or adhesive sheet 11 First main surface 12 Second main surface 20 Protective layer 60 Adhesive L Liquid

Claims (9)

An adhesive or adhesive sheet that retains adhesive or adhesive components, has a structure containing cellulose, and has a thickness of 100 nm to 2 μm. The adhesive or adhesive sheet according to claim 1, wherein the cellulose is a regenerated cellulose having a weight average molecular weight of 100,000 or more. The adhesive or adhesive sheet according to claim 1 or 2, wherein the component is continuously present between the surface of the adhesive or adhesive sheet and the cellulose in the thickness direction of the adhesive or adhesive sheet. .. The adhesive or adhesive sheet according to claim 3, wherein the content of the component in the adhesive or adhesive sheet is 2% by weight or more. The adhesive or adhesive sheet according to any one of claims 1 to 4, wherein the structure is a porous structure. The adhesive or adhesive sheet according to any one of claims 1 to 5, which has an adhesive force of 0.1 N / cm or more. The adhesive or adhesive sheet according to any one of claims 1 to 6, which holds a thermoplastic adhesive or a thermosetting adhesive as the component. The adhesive or adhesive sheet according to any one of claims 1 to 5, which holds an adhesive main agent or a curing agent that cures the adhesive main agent as the component. The adhesive or adhesive sheet according to any one of claims 1 to 8.
A protective layer that is placed on the first main surface of the adhesive or adhesive sheet, is removable from the first main surface, and is permeable to a liquid that dissolves or swells the component.
Laminated body.

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